The deposition of films using a magnetron sputtering system provides enhanced deposition rates through the creation of a magnetic field at the target surface. It is advantageous to produce a high vacuum deposition environment within the vacuum chamber in the magnetron sputtering system. One limit to the creation of a high vacuum inside the vacuum chamber is the number and quality of seals between the vacuum chamber at the outside environment. Some seals can leak, thus preventing the formation of a high vacuum. Positioning and forming a seal suitable for a high vacuum can be problematic.
It is also advantageous in magnetron sputtering systems to increase the magnetic field strength at the target surface. This can be especially true when the target is a magnetic material. One barrier to the strength of the magnetic field is the thickness of the backing plate upon which the target is bonded. The backing plate serves the purpose of cooling the target and providing part of the chamber wall for forming the vacuum chamber for deposition of the target onto a substrate. In conventional systems, the backing plate experiences a pressure differential from the vacuum chamber to atmospheric pressure. This pressure differential places limits on the material properties of the backing plate.
Conventional systems have attempted to increase the magnetic field at the target using a number of methods. Some conventional systems have attempted to strengthen the magnetic field at the target by decreasing the thickness of the backing plate and using a center post to support the backing plate. However, bowing, deflection and buckling of the backing plate can still be caused by the pressure differential between the vacuum inside the chamber and pressure outside the chamber.